Abstract
A new manganese-oxidizing strain FM-2 was screened out from biological activated carbon (BAC) filter column and was identified as Citrobacter freundii. The results of the systematic study on this species are as follows: At 27°C, the optimum pH for Citrobacter sp. FM-2 to remove manganese was 7.0–8.0.The best removal rate of manganese under 27°C, pH 7.0 by FM-2 was reached at 4 d, being 76.2%; Compared with adsorption, biological oxidation played a dominant role in this removing process. Almost 75.7% of manganese was oxidized into oxides by Citrobacter sp and there were some particular oxides analogs generated on the bacterial surface; A 296bp DNA fragment amplified from Citrobacter sp. FM-2 revealed that this species has multicopper oxidase genes. Meanwhile, the phylogenetic tree indicated that compared with other related species, Citrobacter sp. FM-2 has its own evolutional independence.